Rheostat



Mar. 211 1923.

' J. T, RHAMSTINE.

RHEOSTAT.

.FILED Amm. 1922.

Patented Mar. 20., 1925.

JOHN THOMAS RHAMSTINE, 0F DETROIT, MICHIGAN.

RHEOSTAT.

Application led August 8, 19.22. Serial No. 580,477.

To (,LZZ whom may concern.'

Be it known that JOHN THOMAS RHAM- s'rINE, a citizen of the United States, resid-.

ing at Detroit, in the county of lVayne and State of Michigan, has invented certain new and useful Improvements in Rheostats, of which the following is a specification.

The present invention relates to rheostats, and more particularly to a device of this character for use on panel boards of radio apparatus.

An object of this invention is to provide a rheostat which requires but one opening in the panel.; wherein. the resistance element is rotated while the contact brushes are held stationary, insuring a better and more secure connection to the wires which lead into and -from the rheostat.

Another object of the invention is to arovide a drum or revolvable member which is relatively small in size so as to occupy but little space at the back of the panel, and tosc peculiarly arrange a resistance element upon 'the relatively small drum to obtain the desired range of resistances by the usual minute adjustment of the handle and to 0H- sct to a large extent inductance which might otherwise be produced and affect adjacent parts of the apparatus.

`The invention still further aims at the provision oi'.2 a compact device having a rela.- tively wide range of adjustment and which may be quickly and easily mounted upon a panel board or the like in a relatively small opening in the board and which admits of the proper adjustment ot the index arm or linger and the limiting of the device for turning in the necessary direction.

rEhe above, and various other objects and advantages ot this invention will in part be described in, and in part be understood from, the following detailed description of the present preferred embodiment, the same being illustrated in the accompanying drawing wherein:

Figure 1 is a` perspective view of a panel board having a rheostat constructed according to the present invention applied thereto.

iFigure 2 is an enlarged side elevation of the rheostat removed.

Figure 3 is a 'front elevation of the rheotat.

Figure 4t is a rear elevation thereof.

Figure is Afragmentary longitudinal sectipn on line 5 -5 of Figure 4f through a portion of the drum, showing the connection between the resistance coil elements.

Figure 6 is a fragmentary sectional view taken at right angles to Figure 5 substantially on the line 6 6.

Figure 7 is a view similar to Figure 5 but taken on the line 7--7 of Figure 6, and

Figure 8 is a longitudinal 'sectional viewA taken through the rheostat, and showing in dotted lines a portion of the panel upon which the rheostat maybe mounted.

Referring to the drawin 10 designates a panel board, which ma f e the side of a casing or any other suita. le structure upon which the rheostat may be su ported, the term panel being used generica ly throughout as a suitable support for the rheost-at. As best seen in Figure 8, the rheostat comprises a shaft 11 of suitable length and having a smooth cylindrical surface for the major portion of its length, and having at its outer end a. reduced threaded stem 12 upon which is detachably threaded a handle l or kno-b 13. The stem 12 terminates at its inner end in a tapering shoulder 111 which merges into the shaft 11 and against which is bound an index finger or pointer 15 which is flat, apertured at its inner end to loosely receive the stem therethrough, and which at its outer end is provided with a tapering index linger which may be slightly curved or rounded inwardly away from the handle 13. The handle 13 is adapted to be turned up upon the stem and against the pointer 15 for binding the latter against the shoulder 14 after the pointer has been adjusted. The shaft 11 is provided with a freely rotatable bushing 16 provided upon its outer end with a ianged head 17 adapted to engage the outer side of the panel 10, and the bushing is` externally threaded for engagement through au opening in'the panel to firmly support the bushing when it is screwed into the opening. The bushing 16 carries a bracket 18 which is in the form of a lia-t arm having a screw threaded opening at its inner end to receive the bushing 16, the

bushing being adapted to be turned through the lbracket to bind the latter against. the inner side of the panel 10 for firmly locking and/holding the bushing 16 in the panel.

Detachably mounted upon the shaft 11 is a drum 19 of electric nonconducting mate- The mnd i@ mfw be vrovded with a suitduch c L f J u whisk projfec; nwardy m the hmm in ti'czxly ubfmt the opening thmugh the panel @wings 25 fef and they rammed ends and over wwlch. the pointer i5 is adaped to he lops 25j :me j-eimd iogether by u. m 'se when tim h'de is turned. The @Y @mad Ui the vpoi l5 thus dexdn'xnes; h@ pston nf co A Y 'Uw drum 19 and conS-aqnexy it can be read- 23 defm'n'ined the ewth of "ah@ Colli which mi luterposed be Wem ha comme@ E() '0 ofer 25 r@ time wired lessnnc@ acccdiug" @bathe read 9G "21H n which da@ du@ nu :scale:- o'I graduatious E?. E: will 'g 'n y? the (hmm, be univ@ that ,han clement c-omes in h'oug'h :md zur@ driven ndt one Spring Contact i() h@ coil section, such m" *dm drum beas 24, creates ind-latimes in one dref'ton hws ma? i354 while 'he current in passing; aclos tlebridge 95 ming nhs pire F37 und. im@ 'die oppse coil section 9.3 prodmes Coima .or lwulzzilg indu@ me fue f-elfren; passai; '15) dus other con- M). 'it w b9 n 1 each advsmffe 10U le um Section5 d spar/mg 'from a; and modlfxum. m15 dsgn of MG :dat m "une embodiment.

lation and e "a ite-d to near against said resistancc nieiits -for traversing the same upon the turning of said member.

3. A. rlieostat comprising; a drinn, means for turning tlie drinn, al pair of parallel coil sections of resistance material arranged upon tile periphery of the drum and interconnected at one end7 a fixed bracket, a pair of spaced contacts carried by the bracket and bearing against said resistance elements 1for simultaneously traversing the same upon rotation o" the drum.

riieostat comprising a bushing adapted 'to be secured through a support, a bracket carried upon the inner end ot the bushing7 a. shaft mounted to turn in the bushing, a drum ou the inner end of the shaft adjacent the bracket, handle on the outer end of the shaftfor turning the same, a resista-nce coil having parallel sections secured in spaced relation about the drum. and interconnected at one end, and a pair oi: spaced apart contacts n'iounted on the bracket in position to traverse the sections of the coil upon the turning; of the drinn. i

5. i/rrseostat comprising threaded bushn to secured through` a panel and havn liead on cuter end for engageieixt fainst tile outer face oitiie panel, a bracket readed upon the inner end of the bushing and adated to be. bound against the inner side oi the panel and having an overhangarni on its outer end', a shaft mounted to turn in the bushing, a handle on the outer end oi the shaft, a` pointer carried upon the outer of tlie shaft adapted to traverse the panel., drum detachabiy mounted upon opposite ends of each coil section. w contacts carried by tne overhang-ing arm ci: said bracket vadapted to traverse the con sections and to engage with said insulating A.

means upon the turning or" the drum, d stop means carried upon the bracket and. the drum for arresting 'the Increment of the latter to hold the contacts upon said .insnilatn ing means.

6. ln a rheostat, a drum having spaced apart peripheral grooves extending there about and having in one side radial openn ings leading from the grooves, coil sections seated in the grooves and having anchoring; means at opposite ends adapted in said radial openings and said coil Sectio being interconnected at one end, insulating pins mounted in said openings o' the drum between the anchoring devices of said coil sections for binding the anchoring devices in the. drinn and for insulating the tree end. of said coil sections, and a pair oit spaced apart springr contacts adapted to traverse the Coil sections and arranged to engage insulating' pins for liolding the contacts out of engagement with said coil sections.

7. n a rlxeostat a pair of spaced contacts, a pair oi'- coii sections arranged to :traverse the contacts and interconnected at one l and means for relativeijy1 moving til-e sections and the contacts for increasing decreasing resistance of the coil sections be tween the contacts.

8. In a rlieostat, a pair of resistance coil sections arranged in parallel and intercom nected at one end, a pair of contacts aru ranged to traverse the coil sections, means for relatively moving the coil sections and contacts.

In testimony whereof I afiix my Signat ire.

JOHN THOMAS RHLXMSTINE. 

